Replacing mercury with galinstan in Lippmann photography (video)

[ThePhotoChemist]

Hey everyone. Here's a video I slapped together about a plate holder that I slapped together. I was able to make a fairly effective mirror out of galinstan instead of mercury -- but cleaning it off is a whole other problem.

I think next I'm going to try making the holder anaerobic - either by flushing nitrogen, or by filling the thing with mineral oil. I'd be interested in hearing any thoughts you all may have.

 

[nmp]

Hey everyone. Here's a video I slapped together about a plate holder that I slapped together. I was able to make a fairly effective mirror out of galinstan instead of mercury -- but cleaning it off is a whole other problem.

I think next I'm going to try making the holder anaerobic - either by flushing nitrogen, or by filling the thing with mineral oil. I'd be interested in hearing any thoughts you all may have.

Thanks for posting the video. I am extremely intrigued by Lippmann photography. While this galinstan (sound like a place) is no mercury, but sure looks like cumbersome. I suppose the air-surface method does not suffice, otherwise that would be so much simpler.

I have a couple of questions:

1) what type of emulsion do you use. Is this commercial or do you make your own?

2) Trying to figure how this works (still a lot of holes in my understanding) : do you display the "print" with anything in the back or does it also require a mirror like surface to reflect back to form the the multi-color interference pattern?

Fascinating stuff. I like this better than the autochromes...

:Niranjan.

 

[ThePhotoChemist]

Hey there,

I make my own emulsion. I wrote a procedure here, if you're interested. When it works, the air-gelatin boundary can produce some really nice results (all the examples you may see on my site are air-gelatin plates). But it's really hard to get consistently bright plates. Every once in a while one ends up with bright, vivid colors, and I think most of the randomness comes down to development. I've never seen a mercury Lippmann plate, but I hear they're pretty spectacular.

It's a positive process, so the plate you shoot is the final photograph. You view them with reflected light (kind of like a hologram). Often people will cement them to a shallow prism, which splits the surface reflection from the metallic reflection in the emulsion - this enhances the color saturation considerably, but makes them even harder to view. Mercury isn't required for viewing, it's the bright silver grains that reflect the light like little mirrors.

 

[erian]

Many thanks for this video. I now finally understood the mercury part in the process.

Few ideas. Can you coat the plate with something that makes galinstan not to stick? Or something that sticks but could be pealed (or washed) off easily without destroying the emulsion? Kind of sacrificial layer.

I think you need a valve at the top of the holder (perhaps also bottom). This would allow you to pour either oil or lighter than air gas into the holder and contain it. Releasing the valves then allows the alloy to flow in while the liquid/gas flows out.

I have also a question.

Is it possible to scan or photograph the plates with good results to make a good high resolution digital copy?

 

[ThePhotoChemist]

The big problem with an additional layer is that the mirror needs to be in immediate contact with the emulsion. As far as I understand, there really isn't any tolerance to this. I haven't tried it myself, but I've heard that even using aluminum mirror film fails because of the thin layer of aluminum oxide that rapidly forms on the sheet's surface.

Per the gallium wikipedia article, the inside of galinstan thermometers are coated with Gallium (III) oxide to prevent wetting, so if you were to try and develop a coating or incorporate something into the emulsion, that would be a good place to start.

I think a design along those lines is about right. I was doing some thinking - I think pumping the galinstan up from the bottom (with a layer of oil floating on top) may be the way to go. See my highly technical diagram. I bought a test tube and a squeeze bulb, so hopefully I can try that out in a few days.

I don't think scanning would work very well, but tbh I haven't tried. Digitizing these things is a huge PITA. I usually use a digital camera with the optical zoom zoomed all the way out, set up as far from the plate as I can get, with a diffuse light source behind me.

 

[Photo Engineer]

Thinking this over, I believe that there are several low melting alloys that might be used to do this. I have not researched it in years, but there are alloys that melt at room temperature or below that might be better than Gallium.

PE

 

[nmp]

Hey there,

I make my own emulsion. I wrote a procedure here, if you're interested. When it works, the air-gelatin boundary can produce some really nice results (all the examples you may see on my site are air-gelatin plates). But it's really hard to get consistently bright plates. Every once in a while one ends up with bright, vivid colors, and I think most of the randomness comes down to development. I've never seen a mercury Lippmann plate, but I hear they're pretty spectacular.

It's a positive process, so the plate you shoot is the final photograph. You view them with reflected light (kind of like a hologram). Often people will cement them to a shallow prism, which splits the surface reflection from the metallic reflection in the emulsion - this enhances the color saturation considerably, but makes them even harder to view. Mercury isn't required for viewing, it's the bright silver grains that reflect the light like little mirrors.

Thanks, Jon. So much to learn on your blog.

So I had a thought. Please talk me out of it. What happens if you coat on a reflective surface, like metal coated (gold, silver, chrome etc) glass plate (or even a Si wafer) and expose it the other way, i.e. the emulsion facing the lens. Would you not also form the standing waves then? It is a common phenomenon to observe the interference nodes in micro-photolithography. Of course you would have the film on this mirror-like substrate in the end. I am not clear about what that would do the ability to observe the colors.

:Niranjan

 

[ThePhotoChemist]

Thanks, Jon. So much to learn on your blog.

So I had a thought. Please talk me out of it. What happens if you coat on a reflective surface, like metal coated (gold, silver, chrome etc) glass plate (or even a Si wafer) and expose it the other way, i.e. the emulsion facing the lens. Would you not also form the standing waves then? It is a common phenomenon to observe the interference nodes in micro-photolithography. Of course you would have the film on this mirror-like substrate in the end. I am not clear about what that would do the ability to observe the colors.

:Niranjan

You would definitely get standing waves if you did that! I think the big trouble you run into there, though, is that the interference pattern doesn't penetrate all the way through the emulsion -- it's usually limited to so many microns deep from the surface. I can't look right now because I'm at work, but I'd bet they at least mention it in that Herbert Ives Lippmann paper. If you could find a way to remove the emulsion from the mirror and flip it around, I have no doubt you'd be able to see colors! Or maybe if your emulsion was sufficiently thin enough, you wouldn't have to flip it -- but then I'd be worried about the mirror interfering the ability to view it. It's a cool thought though, and it would be really cool if you were able to make it work somehow. I'd definitely be easier to walk around with these "dry plate" instead of lugging a bath of molten metal.

 

[nmp]

I am sure there is a deal-breaker somewhere in there....Lippmann got a Nobel for his work on this after all.

...interference pattern doesn't penetrate all the way through the emulsion -- it's usually limited to so many microns deep from the surface.

Here is my understanding. The light traverses the glass plate, then thru the emulsion, gets reflected at the Hg/emulsion interface, interferes with the incoming wave to produce the standing waves. There is an attenuation of the standing waves as light is absorbed in the medium before getting out the back thru the glass. So the pattern at the Hg/emulsion interface (which becomes the top surface as Hg is removed) will be strongest, not so much at the you go deeper into the emulsion.

In the case of metallized plate exposed the right way, the situation is reversed. The strongest waves would still be at the metal/emulsion interface, but weakening as you move to the emulsion/air surface.

If my understanding of this physics is correct (won't be surprised if I am missing some key point,) then the total quantity/quality of the waves will be similar as before, with the difference being the stack of the plates will be flipped over. You also do not have an extra absorption of the incident light by the glass as it is the case in the Hg method.

If you could find a way to remove the emulsion from the mirror and flip it around, I have no doubt you'd be able to see colors! Or maybe if your emulsion was sufficiently thin enough, you wouldn't have to flip it -- but then I'd be worried about the mirror interfering the ability to view it.

This is the part where the pitfalls probably are. To flip the emulsion, perhaps it can be glued on to an another carrier, may be even the prism that would be used to display and then somehow de-laminate the emulsion from the metallised glass. Bad adhesion will come in real handy here...

Just some theoretical thoughts on my part...I will probably never will do this myself.

:Niranjan.

 

[ThePhotoChemist]

Quick update: I tried this using mineral oil, and boy did this not work. Most importantly, as the oil rose across the glass plate in the holder, it formed pockets between it and the galinstan. Re-filling it, knocking it around etc only worsened things, until there seemed to be just a ton of dull gallium oxide all over the place. And of course, breaking the kit down ended in an oily mess.

I do have high hopes for trying this again, but with nitrogen. I was very careful when cleaning up -- after I washed the galinstan with NaOH, I used a syringe to move it back to its container. I have a small layer of mineral oil in its container, and made sure to empty the syringe under that. It's appearance is significantly brighter, though the top did eventually skin over. I think if the holder can be sufficiently flushed with nitrogen, and the galinstan introduced and removed with a syringe, we can achieve pretty good results.

 

[J 3]

Quick update: I tried this using mineral oil, and boy did this not work. Most importantly, as the oil rose across the glass plate in the holder, it formed pockets between it and the galinstan. Re-filling it, knocking it around etc only worsened things, until there seemed to be just a ton of dull gallium oxide all over the place. And of course, breaking the kit down ended in an oily mess.

Question - How high of a temperature can these holographic plates take before they are damaged in some way?

The reason I ask is because there are several low-ish alloys of indium, that fall near a hot summer day in their melting point. For instance this alloy (117-f-47) which is running about $65 a pound - https://www.belmontmetals.com/product/117-f-47-c-low-melting-alloy/

It has a melting point of 47C / 113F.
Nominal formula:

• 44.7% Bi
• 5.3% Cd
• 22.6% Pb
• 19.1% In
• 8.3% Sn

This isn't non-toxic because of the lead and cadmium but it would be much safer than mercury I'd think and there is no Gallium to foul up the plate. I have no idea if it'd work of course. I'd love to try but I'm not at the point of making holographic emulsions yet.